The semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC design and material have produced generations of ICs where each generation has smaller and more complex circuits than previous generations. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased.
As the semiconductor device scaling down continues, challenges in fabrication may arise. For example, the shrinking distances between various semiconductor components may lead to bridging or electrical shorting problems, which would degrade semiconductor device performance or even cause device failures.
Therefore, although existing semiconductor fabrication methods have been generally adequate for its intended purposes, they have not been entirely satisfactory in every aspect.